import random
stu = [ ]
for c in 'ABCDEFGHI':
    yz = (c, random.randint(40,100))
    stu.append(yz)


print(stu)
score = sum([s[1] for s in stu])
print('平均分:',score / len(stu))
stu2 = [s for s in stu if s[1] < 60]
print('不及格人数:', len(stu2))